Endothelial Progenitor Cells as Mediators of the Crosstalk between Vascular Repair and Immunity: Lessons from Systemic Autoimmune Diseases.

From the discovery of Endothelial Progenitor Cells (EPC), these bone marrowderived precursors have been placed as crucial mediators of the endothelial repair. Accordingly, altered levels and function of EPC have been found in different scenarios of CV risk. Despite the fact that EPC exhibit important characteristics which support a link of this cell subset with a number of inflammatory and immune networks, little is known on the actual mediators involved and the clinical relevance of these features. Systemic diseases are generally hallmarked by a vascular repair failure and increased cardiovascular disease occurrence, EPC impairment having a pivotal role. Because of their immunemediated etiology, this group of conditions represents an invaluable scenario to unravel the connections between immune dysregulation and EPC dysfunction. In the present review, we summarize the current knowledge regarding the cutting-edge area of the modulation of EPC levels and function by inflammatory cytokines in systemic diseases. We also address the possibility of the available immunomodulatory drugs to counteract this situation. Finally, due to the emerging role of the vitamin D as a common mediator in the immune system and the cardiovascular axis, we cover the topic of the role of vitamin D as a potential player in the inflammatory-mediated EPC dysfunction in systemic diseases.